Performance of a hyperprolific rabbit line I. Litter size traits

Abstract

Summary Litter size traits of a maternal line of meat rabbits, line H, founded by selecting on hyperprolificacy, were studied to check its prolificacy. Due to health problems related to the putting together of animals with different origins and to the genetic heterogeneity of the commercial population from which the new line (line H) was founded, line H was compared to the best maternal line available (line V) and with crossbred does (A × V) of high litter size. The comparison took place on four farms and involved 858 females. The analysis of litter size traits showed that line H had superior prolificacy compared with crossbred females and the average of line V and crossbred females, which was around 0.5–0.8 young (p < 0.05). The contrasts between line H and line V were always favourable to line H, by around 0.5 pups, but were not significant (p = 0.06). The differences between the two lines, however, changed with parity order: they were null for first and second parity but reached values of one young and even more for superior parity orders. The differences in prolificacy did not have consequences on the fertility of the females as there were no differences in kindling interval for the animals studied. It can be concluded that hyperprolific selection has been successful in rabbits, and the new line could play an important role as a maternal line in rabbit production for meat. Zusammenfassung Leistung fruchtbarer Kaninchenlinien. I. Wurfgrößenmerkale, Wurfgrößenmerkale der maternalen Linie H von Mastkaninchen, selektiert auf hohe Fruchtbarkeit, wurden überprüft. Aufgrund hygienischer Bedenken bei Zusammengühren kommerzieller Herkünfte konnte sie nur mit der verfüfbaren Mutterlinie V vergliche werden sowie mit entsprechenden Kreuzungen (A × V). Die Untersuchung umfaßte 858 Muttertiere auf 4 Betrieben. Wurfgröße von H war Kreuzungen und Linie V um ca. 0.5 bis 0.8 Junge überlegen. Kontraste mit Linie V bgünstigten immer Linie H, um ca. 0.5 Junge. (p < 0.06). Die Linienunterschiede änderten sich mit Wurffolge ‐ null bei ersten bis au 1 bei späten Würfen. Die Fruchtbarkeit war durch größere Würfe nicht beeinträchtigt, das Zwischenwurfintervall änderte sich nicht. Selektion auf Wurfgröße ist bei Kaninchen erfolgreich und die neue Linie sollte in der Kaninchenmast eine wichtige Rolle spielen. Resumen Se estudiaron los caracteres de prolificidad en una nueva IRnea de conejo de carne fundada aplicando un esquema de selección por hiperprolificidad. La nueva línea (línea H) se comparó con dos tipos de animales de prolificidad superior a la población a partir de la cuál se fundó (línea V y hembra cruzada A×V). El experimento se realizò en cuatro granjas e involucró a 858 hembras. El análisis de la prolificidad indica que la línea H fue superior en 0.5–0.8 gazapos al cruce A×V y al promedio de la línea V con la hembra cruzada. Los contrastes entre la línea H y la línea V fueron siempre favorables a la línea H, en torno a 0.5 gazapos, aunque no resultaron significativos (p = 0.06). Al analizar la prolificidad en función del or...

Effect of freezing extender composition and male line on semen traits and reproductive performance in rabbits

“…Animals A total of 252 White New Zealand rabbit does (females with more than one parity without suckling any young) and 20 mature bucks belonging to two maternal lines (H and LP) were used. Line H was founded applying hyperprolific selection (Cifre et al, 1998), and line LP was founded applying hyperlongevity selection and an independent culling level near the average for prolificacy (Sanchez et al, 2008). Does and males were housed in flat deck cages with light alternating on a cycle of 16 light hours and 8 dark hours; they were fed with the same commercial diet (17.5% CP, 2.3% ether extract, 16.8% crude fibre, 2.600 kcal DE/kg) and had free access to water.…”

Comparison of the effect of two different handling media on rabbit zygote developmental ability

“…Mature rabbit does from a synthetic line, called H [7], were mated twice with fertile bucks, receiving an intramuscular GnRH injection (20 µg, Fertagyl, Intervet, Spain) at the same time. At 12-13 h after mating, eggs were recovered immediately after euthanasia of donor females by flushing oviducts with either Dulbecco phosphate buffered saline (PBS, D5773, Sigma, Spain) supplemented with 20% (v/v) FCS (hereafter: s-PBS) or with Ham F-10 (N6635, Sigma, Spain) supplemented with 20 mM HEPES (11344, GibcoBRL, LifeTech, Spain) and 20% (v/v) FCS (hereafter: h-Ham).…”

Selection for ovulation rate in rabbits

“…After its constitution, the line was selected for litter size at weaning. The hyperprolific line was contrasted to other maternal lines, showing its superiority over crossbred females (around 0.5 young weaned more; Cifre et al, 1998) and over purebred females (0.70 to 1.40 young weaned more; Cifre et al, 1998;Ragab and Baselga, 2011).…”

“…In rabbits, the only hyperprolific line was founded by Cifre et al (1998) by applying hyperprolific criteria and embryo cryopreservation techniques. Selection was performed on hyperprolific does from a large commercial population following criteria detailed by Cifre et al, (1998).…”

“…Selection was performed on hyperprolific does from a large commercial population following criteria detailed by Cifre et al, (1998). After its constitution, the line was selected for litter size at weaning.…”